Study of zirconia surface modification by femto-second laser.

采用飞秒激光工艺对氧化锆口腔修复体表面进行修饰，以提高其附着强度。在本研究中，在表面上采用了两种线性微槽排列。考察了胶粘剂抗剪强度的增加以及对胶粘剂强度的影响。采用脉冲能量为9μJ、光斑进给量为5μm/脉冲的飞秒激光系统对直径为5mm的全烧结氧化锆圆端面进行加工。通过该工艺可获得深度为51μm、宽度为53μm的微凹槽。在这项研究中，两种类型的直线槽对齐产生。在第一次对准中，直槽线平行。在第二组实验中，两组平行凹槽相互垂直。将改性的氧化锆表面粘合到Crearfil DC Core Auto-mix ONE （Kuraray Medical Inc.,Japan）的镜面上，并将玻璃载玻片表面转移到该镜面上。使用的黏合剂为Crearfil SA Cement Auto-mix universal （Kuraray Medical Inc.,Japan）。厚度为50μm，圆形粘结区直径为4mm。粘接抗剪强度试验在万能试验机（DCS-5000, Shimazu Co.）上进行，十字头速度为1mm/min。具有线性平行微沟槽的氧化锆表面的黏附剪切强度为35.8(sd:6.0) MPa，而无沟槽的氧化锆表面的黏附剪切强度为23.4(sd:9.2) MPa。交叉型微沟槽的表面强度可达46.8 MPa (S.D:5.5) MPa。飞秒激光表面改性在氧化锆修复体表面形成微凹槽，是提高氧化锆修复体与水泥结合强度的有效手段。

We modified the surface of zirconia dental prostheses through femto-second laser process in order to improve the adhesion strength of them. In this study, two alignments of linear micro-grooves were employed on the surface. The increase of adhesion shear strength and the effect of the alignment on the strength were examined. A round end surface of a fully-sintered zirconia bar with diameter of 5mm was processed with femto-second laser system, which provided pulse energy of 9μJ and spot feed of5μm/pulse. Through the process, micro grooves with depth of 51μm and width of 53μm were obtained. In this study, two types of alignments in linear grooves were produced. In the first alignment, straight groove lines were parallel. In the second, two groups of parallel grooves were perpendicular to each other.The modified zirconia surfaces were bonded to the mirror surface of Crearfil DC Core Auto-mix ONE (Kuraray Medical Inc.,Japan) to which the surface of a glass slide was transferred. The adhesion used was Crearfil SA Cement Auto-mix universal (Kuraray Medical Inc.,Japan). The thickness was 50μm and the diameter of round bonded area was 4mm. Adhesion shear strength tests were carriedout on the universal testing machine(DCS-5000, Shimazu Co.), in which the speed of cross head was 1mm/min.The adhesion shear strength of zirconia surface with linear parallel microgrooves was35.8(S.D.:6.0) MPa, while the strength of original surface without grooves was23.4(S.D.:9.2) MPa. Moreover, the strength of the surface with cross-typed microgrooves increased up to 46.8(S.D.:5.5) MPa. The surface modification through femto-second laser process, in which micro-grooves were formed on it, is very useful tool for improving the adhesion strength between zirconia prostheses and cements.